[Clinicopathological and genetic characteristics of congenital cystic adenomatoid malformation of lung and its associated lung cancer in adults]

Objective: To investigate the clinicopathological features and genetic characteristics of congenital cystic adenomatoid malformation (CCAM) of lung and CCAM associated lung cancer in adults. Methods: A total of 13 cases of CCAM of lung in adults, diagnosed from June 2015 to May 2023, were collected from the Department of Pathology, Shanghai Pulmonary Hospital, Tongji University School of Medicine, China. Their histopathological features were correlated with probable development into lung cancer. Next-generation sequencing was performed on the benign and malignant areas of all cases. Results: The pathological classification of all cases were of CCAM of lung type 1. There were 4 male and 9 female cases, age ranged from 18 to 65 years, with a mean age of 41 years. Six cases were accompanied by lung cancer, all of them were mucinous adenocarcinoma. Next-generation sequencing showed no gene mutation in 2 of the 13 cases; KRAS mutations in exon 2 were detected in 7 cases, in which there were 6 cases complicated with lung mucinous adenocarcinoma and no matter in the malignant or benign regions, the same case exhibited the same mutation sites in KRAS gene. Conclusions: CCAM of the lung is a congenital disease, and in adults, type 1 is most commonly found in the pathological classification, and it is often accompanied by cancer. Gene mutations are frequently detected in CCAM of the lung, KRAS being the most recurrent mutation which may play an important role in the carcinogenesis.

[Application of the WHO Classification of Thoracic Tumors (2021) grading system in invasive pulmonary adenocarcinoma and its correlation with the targeted genes' variations]

Objective: To investigate the applicability of the 2021 WHO classification of thoracic tumors' new grading system for invasive pulmonary adenocarcinoma (IPA) with different clinical stages and its correlation with the characteristics of targeted genes' variation. Methods: A total of 2 467 patients with surgically resected primary IPA in Shanghai Pulmonary Hospital, Shanghai, China from September to December 2020 were retrospectively analyzed. Eligible cases were graded using the new grading system of IPA of the 2021 WHO classification of thoracic tumors. The clinicopathological data and targeted-gene abnormality were collected. The utility of new grading system of IPA in different clinical stages was investigated. The correlation of clinicopathological features and targeted-gene abnormality in different grades of IPA were compared. Results: All 2 311 cases of IPA were included. There were 2 046 cases of stage Ⅰ IPA (88.5%), 169 cases of stage Ⅱ (7.3%), and 96 cases of stage Ⅲ (4.2%). According to the new classification system of IPA, 186 cases (9.1%), 1 413 cases (69.1%) and 447 cases (21.8%) of stage-Ⅰ adenocarcinoma were classified as Grade 1, Grade 2 and Grade 3, respectively. However, there were no Grade 1 adenocarcinomas in stages Ⅱ and Ⅲ cases. Among stage-Ⅱ and Ⅲ IPA cases, there were 38 Grade 2 cases (22.5%) and 131 Grade 3 cases (77.5%), and 3 Grade 2 cases (3.1%) and 93 Grade 3 cases (96.9%), respectively. In stage-Ⅰ cases, no tumor cells spreading through airspace (STAS), vascular invasion or pleural invasion was found in Grade 1 of IPA, while the positive rates of STAS in Grade 2 and 3 IPA cases were 11.3% (159/1 413) and 73.2% (327/447), respectively. There was a significant difference among the three grades (P<0.01). Similarly, the rates of vascular and pleural invasion in Grade 3 IPA cases were 21.3% (95/447) and 75.8% (339/447), respectively, which were significantly higher than those of 1.3% (19/1 413) and 3.0% (42/1 413) in Grade 2 (P<0.01). EGFR mutational rates in Grades 1, 2 and 3 IPA were 65.7% (94/143), 76.4% (984/1 288) and 51.3% (216/421), respectively. The differences among the three grades were statistically significant (P<0.01). No fusion genes were detected in Grade 1 IPA, while the positive rates of ROS1 and ALK fusion genes in Grade 3 were 2.4% (10/421) and 8.3% (35/421), respectively, which were significantly higher than that of 0.5% (7/1 288) and 1.6% (20/1 288) in Grade 2 (P<0.01). In stage-Ⅱ cases, only EGFR mutation rate in Grade 2 adenocarcinoma (31/37, 83.8%) was higher than that in Grade 3 adenocarcinoma (71/123, 57.7%; P<0.01). However, the correlation between the new grade system of IPA and the distribution characteristics of targeted-gene variation cannot be evaluated in stage Ⅲ cases. Conclusions: The new grading system for IPA is mainly applicable to clinical stage-Ⅰ patients. Tumor grades of IPA are strongly correlated with the high-risk factors of prognosis and the distribution features of therapeutic targets. It is of great significance and clinical value to manage postoperative patients with early-stage IPA.

[Clinicopathological and genetic characteristics of bronchial sialadenoma papilliferum: report of four cases]

Objective: To investigate the clinicopathological, immunophenotypic, and molecular genetic features of bronchial sialadenoma papilliferum (BSP). Methods: Four cases of BSP collected at the Shanghai Pulmonary Hospital from May 2018 to June 2021 were retrieved and analyzed. These cases were evaluated for their clinical, histological, immunohistochemical (IHC) and genomic features. The patients were followed up and relevant literature was reviewed. Results: All four patients were male, aged from 55 to 75 years (mean 62 years), with tumor diameter of 6 to 21 mm (mean 13.5 mm), and lesions were located in the left lower lobe (n=2), right lower lobe (n=1), and trachea (n=1). They were characterized by a combination of surface exophytic endobronchial papillary proliferation and an endophytic two-cell layered ductal structure. IHC staining showed that CK7 and EMA were strongly positive in ductal epithelium; p63, p40, CK5/6 were positive in ductal and papillary basal cells; SOX10 was positive in ductal epithelium and basal cells; S-100 was positive in basal cells and ductal epithelium in two cases. Next generation sequencing showed that two cases harbored BRAF V600E mutation. Conclusions: BSP is an extremely rare primary lung tumor arising from the salivary gland under bronchial mucosa. The primary treatment choice of this tumor is complete surgical resection. The diagnosis and differential diagnosis of this tumor depend on classic histomorphologic and IHC features, and BRAF V600E gene mutation can be detected.

[Pathological assessment of non-small cell lung cancer resection specimens after neoadjuvant therapy]

Objective: To pathologically evaluate the surgically resected specimens of three different therapies (neoadjuvant chemotherapy, neoadjuvant targeted therapy and neoadjuvant immunotherapy combined with chemotherapy) for non-small cell lung cancer. Methods: One-hundred and thirteen cases of post neoadjuvant therapy non-small cell lung cancer specimens were collected at Tongji University Affiliated Shanghai Pulmonary Hospital from January 2000 to March 2020. There were ninty patients receiving neoadjuvant chemotherapy (chemotherapy group;26 cases of adenocarcinoma and 64 cases of squamous cell carcinoma), 13 patients receiving neoadjuvant targeted therapy (targeted group;13 cases of adenocarcinoma) and 10 patients receiving neoadjuvant immunotherapy combined with chemotherapy (immune combined chemotherapy group;4 cases of adenocarcinoma and 6 cases of squamous cell carcinoma). They were evaluated for histologic tumor regression responses (necrosis, inflammatory cell infiltration, cholesterol crystal deposition, foam cell infiltration, reactive granuloma and interstitial collagenous formation) and pathological responses [main pathological response (MPR) and complete pathological response (PCR)]. Results: Chemotherapy group, targeted group and immune combined chemotherapy group all showed degenerative changes in residual tumor cells, increased atypia, various degrees of necrosis, foam cell aggregation, cholesterol cleft, inflammatory cell infiltration, and reactive granuloma in the tumor bed. Histologic characteristics of tumor regression reaction were not different between these three groups (P>0.05); the highest percentage of necrosis in the targeted group and immune combined chemotherapy group was only 10% and 20%, respectively, while that in the chemotherapy group was as high as 80%. One case of adenocarcinoma in immune combined chemotherapy group had tumor regression bed. The MPR rates of adenocarcinoma in chemotherapy group and squamous cell carcinoma in chemotherapy group were 35% (9/26) and 64% (41/64), respectively; the MPR ratio of targeted group was 2/13; the MPR ratio of adenocarcinomain immune combined chemotherapy group and squamous cell carcinoma in immune combined chemotherapy group were 2/4 and 2/6, respectively. The PCR rates of adenocarcinoma in chemotherapy group and squamous cell carcinoma in chemotherapy group were 11% (3/26) and 3% (2/64), respectively; the PCR ratio of targeted group was 0/13; the PCR ratio of adenocarcinomain immune combined chemotherapy group and squamous cell carcinomain immune combined chemotherapy group were 0/4 and 1/6, respectively. Conclusions: Different neoadjuvant therapy may cause various histopathological changes in non-small cell lung cancer: more necrosis is noted in the chemotherapy group and regression bed frequently appears in the immune combined chemotherapy group. In the immune combined chemotherapy group, there are significant lymphoplasmacytic infiltration and lymphoid follicle formation in the lung parenchyma beside the tumor bed.

[Research advances in the v-raf murine sarcoma viral oncogene homolog gene mutation in ameloblastoma]

V-raf murine sarcoma viral oncogene homolog B1 (BRAF) is a pro-oncogene, which is one member of the RAF family. Mutated BRAF is found in approximately 8% of human tumors. BRAF gene mutations lead to continuous activation of the mitogen-activatd protein kinase (MAPK) pathway, which resulting in abnormal cell proliferation and tumorigenesis. In recent years, recurrent MAPK signaling mutations were identified in ameloblastoma, among which BRAF-V600E is the most prominent type. This provides new strategies for the targeted treatment of ameloblastoma. This paper reviewed the latest advances in BRAF gene mutation associated with ameloblastoma and its potential clinical significance.

[Clinicopathologic features and genetic profile of the redefined large cell lung carcinoma]

Objective: To investigate the clinicopathologic features and genetic profile of large cell lung carcinoma (LCC) redefined by new classification. Methods: Basing on 2015 WHO classification criteria in redefining large cell lung carcinoma, the expression of specific markers (TTF1, Napsin A, p40, CK5/6, CK, vimentin and ZEB1) was detected by immunohistochemistry and D-PAS staining in 303 surgically-removed lung specimens previously diagnosed as large cell lung carcinoma. The clinicopathologic and genetic characteristics (including EGFR, KRAS, BRAF, ALK and ROS1 gene mutation) were analyzed. Results: Based on the new definition of LCC, 116 cases (116/303, 38.3%) of LCC formerly diagnosed were reclassified as solid adenocarcinoma, 49 cases (49/303, 16.2%) as squamous cell carcinoma, 6 cases (6/303, 2.0%) as adenosquamous carcinoma, 22 cases (22/303, 7.3%) as spindle cell carcinoma and only 110 cases (110/303, 36.3%) as large cell carcinoma. Redefined LCCs were characterized as middle-age (range 40-80), male (102/110, 92.7%) and smoking patients (64/110, 58.2%) with intermediate-advanced stage. Among 110 cases, 9 cases with EGFR mutation and 10 cases with KRAS mutation and 1 case with ALK fusion were found. No BRAF and ROS1 alterations were identified. Conclusions: According to the new classification, LCCs formerly diagnosed are mostly reclassified as adenocarcinoma and non-keratinizing squamous cell carcinoma. The newly defined LCC may significantly benefit from clinical therapy.

Multiphoton route to ZnO nanowire lasers

With intense femtosecond laser excitation, multiphoton absorption-induced stimulated emission and laser emission in ZnO bulk crystal and nanowires have been demonstrated at room temperature. UV-stimulated emission peaks appeared in both bulk crystal and nanowires when the excitation exceeded certain thresholds, and a sharp lasing peak with a linewidth of ~0.5 nm was observed from ZnO nanowires. The emission properties were attributed to the band-edge emission of the recombination of carriers excited by two- and three-photon absorption processes in the wide-bandgap semiconductor.

Sphingolipids as biomarkers of fumonisin exposure and risk of esophageal squamous cell carcinoma in china

OBJECTIVE

Ecologic studies of esophageal squamous cell carcinoma (ESCC) have reported an association with consumption of maize contaminated with Fusarium verticillioides, which produce fungal toxins referred to as fumonisins. Fumonisins disrupt sphingolipid metabolism and serum sphingolipids have been proposed as biomarkers of fumonisin exposure. We conducted a prospective nested case-control study to examine the relationship between serum sphingolipids and ESCC incidence.

METHODS

Cases and controls were selected from a large prospective trial conducted in Linxian, People's Republic of China. Ninety-eight ESCC cases were randomly selected from the 639 incident ESCC ascertained during the initial 5.25 years of follow-up: 185 controls were also randomly selected based on the distribution of cases among six age and sex strata. Concentrations of sphinganine and sphingosine were determined by high-performance liquid chromatography in serum collected at the study baseline.

RESULTS

No significant associations were found between serum sphingosine, sphinganine, or the sphinganine/ sphingosine ratio and ESCC incidence in conditional and unconditional logistic regression models with adjustment for age, sex, tobacco use. and alcohol use.

CONCLUSION

Our study is the first prospective study to assess the relationship between sphingolipid levels, as biomarkers of fumonisin exposure, and cancer incidence. We found no significant association between sphingolipid levels and risk of ESCC.

Prospective study of tooth loss and incident esophageal and gastric cancers in China

OBJECTIVE

To determine the association between tooth loss and the risk of developing esophageal squamous cell carcinoma, gastric cardia adenocarcinoma, or gastric non-cardia adenocarcinoma in a prospective study.

METHODS

Cox proportional hazards regression was used to examine these associations in a 28,868-person cohort followed prospectively for 5.25 years. The baseline questionnaire included questions regarding tooth loss, and individuals reporting lost teeth had their teeth counted by study personnel. The analytic cohort included 620 esophagus, 431 gastric cardia, and 102 gastric non-cardia cancer cases.

RESULTS

Tooth loss was associated with a significantly elevated risk of developing all three cancers. When examined as median splits, tooth loss was associated with a relative risk (RR) (95% confidence interval, CI) of 1.3 (1.1-1.6) in the esophagus, 1.3 (1.0-1.6) in the gastric cardia, and 1.8 (1.1-3.0) in the gastric non-cardia. Further analysis demonstrated that this increased risk was most strongly associated with the loss of the first few teeth and was primarily confined to the younger members of our cohort.

CONCLUSIONS

In this cohort tooth loss increased the risk of developing upper gastrointestinal cancer. We hypothesize that this may be related to alterations in oral bacterial flora and subsequent increases in the in-vivo production of carcinogens such as nitrosamines.

A cross-sectional study of human serum sphingolipids, diet and physiologic parameters

Sphinganine and sphingosine, the two sphingoid base backbones of sphingolipids, are highly bioactive compounds that are of increasing interest to nutritionists because they occur in food and their metabolism can be altered by fungal toxins that contaminate some foods. Nonetheless, no studies of diet and sphinganine or sphingosine concentrations in serum have yet been reported. Here we describe a cross-sectional study of 265 residents of Linxian, People's Republic of China, which examines potential demographic, physiologic and dietary correlates of serum sphinganine and sphingosine in this population. Median concentrations of serum sphinganine and sphingosine were compared among strata for 29 different variables. For sphinganine, no significant differences were found. For sphingosine, significant differences were seen among strata of age, menstruation status, serum cholesterol, carotenoids, retinol, tocopherols, fresh and dried vegetable and fresh fruit consumption. Using multivariate linear regression with stepwise selection, we found that the significant predictors for serum sphingosine included total tocopherols, age, serum selenium and retinol, with a final R(2) = 0.22; for sphinganine, tooth loss was the sole correlate, with R(2) = 0.015. Analyses using ranked sphingolipid data or principal components analysis, to simplify the food variables, did not materially alter these results. This study represents the largest report of human serum sphingolipid concentrations to date and provides insight into potential explanatory variables that can be incorporated into future studies.

[The trends and preventive strategies of esophageal cancer in high-risk areas of Taihang Mountains, China]

OBJECTIVE

To analyze and predict the trends of incidence and mortality rates of esophageal cancer in areas of Taihang Mountains, and explore the strategies for facilitating the reduction of the incidence and mortality of esophageal cancer.

METHODS

The data were collected from Linxian and Cixian Counties registries between 1988-1997. The trends of the incidence and mortality rates for esophageal cancer had been fitted and predicted by the model of BP (Back Propagation) Neural Networks. Then Linqi Xiang in Linxian County was taken as an example, to determine the power for reducing incidence and mortality of esophageal cancer using endoscopic technology as an early detection and treatment method.

RESULTS

There were slowly declining trends for both incidence and mortality rates during past 10 years in Taihang Mountains. The predicting rates of the esophageal cancer incidence in 2,002 are 115. 70/100,000 for male and 79.88/100,000 for female; mortality rates are 94.00/100,000 and 56.29/100,000 respectively. Both incidence and mortality rates a still in high level. But when using endoscopic technology as an early detection and treatment method, the incidence rate is nearly 1/3 of a control group and the power is 88.30% at the end of eight years. The mortality rate is 1/4 of the control group and power is 89.44% after five years intervention (both powers based on 0.05 significant levels).

CONCLUSIONS

The incidence and mortality rates for esophageal cancer are still on high levels in Taihang Mountains. We should continue to enhance our preventive effort there. After using endoscopic technology as an early detection and treatment method, the incidence and mortality rates will be decreased markedly during 5 to 8 years. It is recommended to implement a large-scale secondary prevention strategy in these areas.

[The significance of secondary prevention of cancer in China]

During past twenty years (1973-1992), the cancer mortality was increasing significantly in China. For cancer prevention and control nationwide, the primary prevention is important. Pity is that it usually takes longer time to decrease cancer mortality and liable to benefit younger generation. In practice, the secondary prevention, which put emphasis on the massive screening, early detection and early treatment, would decrease the cancer mortality as well as cancer incidences in relatively short time. Therefore, it would contribute much to the local social and economic development and improve the health insurance. In the high risk areas of cancers, such as cervical, esophageal, gastric, liver and nasopharyngeal cancers, the secondary prevention could be carried out as more effective strategy for cancer prevention in China.

Prospective study of serum selenium levels and incident esophageal and gastric cancers

BACKGROUND

From March 1986 through May 1991, we conducted a randomized nutritional intervention trial, the General Population Trial, in Linxian, China, a region with epidemic rates of squamous esophageal and adenomatous gastric cardia cancers. We found that participants who received selenium, beta-carotene, and vitamin E had significantly lower cancer mortality rates than those who did not. In the current study, we examined the relationship between selenium levels measured in pretrial (1985) sera from participants and the subsequent risk of developing squamous esophageal, gastric cardia, and gastric non-cardia cancers during the trial.

METHODS

This study was designed and analyzed in accord with a stratified case-cohort sampling scheme, with the six strata defined by sex and three age categories. We measured serum selenium levels in 590 case subjects with esophageal cancer, 402 with gastric cardia cancers, and 87 with gastric non-cardia cancers as well as in 1062 control subjects. Relative risks (RRs), absolute risks, and population attributable risk for cancers were estimated on the basis of the Cox proportional hazards models. All statistical tests are two-sided.

RESULTS

We found highly significant inverse associations of serum selenium levels with the incidence of esophageal (P: for trend <10(-4)) and gastric cardia (P: for trend <10(-6)) cancers. The RR and 95% confidence interval (CI) for comparison of highest to lowest quartile of serum selenium was 0.56 (95% CI = 0.44-0.71) for esophageal cancer and 0.47 (95% CI = 0.33-0.65) for gastric cardia cancer. The population proportion of these cancers that is attributable to low selenium levels was 26.4% (95% CI = 14.45-38.36). We found no evidence for a gradient of serum selenium associated with incidence of gastric non-cardia cancer (P: for trend =.96), with an RR of 1.07 (95% CI = 0.55-2.08) for the highest to lowest quartile of serum selenium.

CONCLUSIONS

Our study supports findings from previous prospective studies and randomized trials that variations in selenium levels affect the incidence of certain cancers. In the United States, where intervention trials of selenium are in the planning stages, consideration should be given to including populations at high risk for squamous esophageal and gastric cardia cancers.

Detection of a human parvovirus intrauterine infection with the polymerase chain reaction

OBJECTIVE

To detect human parvovirus B19 intrauterine infection in pregnancy with the polymerase chain reaction (PCR).

STUDY DESIGN

DNA of chorionic villi and amniotic fluid was extracted and the gene of human parvovirus B19 amplified with PCR.

RESULTS

The study analyzed 61 specimens of chorionic villi and 26 specimens of amniotic fluid and found two positive specimens of chorionic villi and 1 positive specimen of amniotic fluid.

CONCLUSION

The vertical transmission of human parvovirus B19 infection in early pregnancy may be a pathway of intrauterine infection. Chorionic villus sampling in early pregnancy and PCR could be developed as a method of prenatal diagnosis of human parvovirus B19 intrauterine infection.

Detection of Chlamydia trachomatis intrauterine infection using polymerase chain reaction on chorionic villi

OBJECTIVE

To detect Chlamydia trachomatis intrauterine infection in the early pregnancy by using chorionic villi.

METHOD

The C. trachomatis infection in pregnant women was investigated by cervical specimens and Clearview kits. DNA of chorionic villi was extracted and the gene of a major outer membrane protein of C. trachomatis was amplified by polymerase chain reaction (PCR).

RESULTS

120 cervical specimens of the pregnant women were analyzed and 10 cervical specimens were positive for C. trachomatis infection. In this study, the prevalence of C. trachomatis infection was approx. 8.3%. Fifty-nine specimens of chorionic villi and three positive specimens of C. trachomatis infection were analyzed by PCR. The incidence of C. trachomatis intrauterine infection in the early pregnancy was 5.1%.

CONCLUSION

The vertical transmission of C. trachomatis infection in the early pregnancy may be a pathway of intrauterine infection. Chorionic villus sampling in early pregnancy and the PCR method could be developed as a technique for prenatal diagnosis of C. trachomatis intrauterine infection.

[A report of epidemiology investigation on 222 infants with tetanus in Pingdingshan City from 1990 to 1991]

A total of 222 in-patients with tetanus had been investigated in Ping Ding Shan City (including 4 counties) from 1990 to 1991. The incidence in 1990 was 62.8/10(5), the special incidence was 2.44/1000. But in 1991, they were 48.1/10(5) and 1.97/1000, respectively. The male-to-female ratio was 3:1. 89.64% infants came from the countryside, and 99.6% infants were delivered in an old way.

Detection of congenital cytomegalovirus infection by using chorionic villi of the early pregnancy and polymerase chain reaction

OBJECTIVE

To detect congenital cytomegalovirus (CMV) infection of chorionic villi in early pregnancy.

METHODS

Extraction of DNA of chorionic villi and amplification of the gene of major immediate-early (MIE) antigen of CMV using a polymerase chain reaction (PCR).

RESULTS

Sixty-eight specimens of chorionic villi and 16 specimens were positive for CMV infection by PCR. The incidence of congenital CMV infection in the first trimester of pregnancy was 23.5%.

CONCLUSIONS

The risk of transmission of CMV from mother to fetus in early pregnancy is very high and potential CMV carriers may transmit CMV to their fetus in early pregnancy.

Anti-FD4 idiotypic antibody mimicking human gastric cancer-associated antigen

Rabbits were immunized with the Fab fragment of a murine monoclonal antibody (McAb) PD4 against human gastric cancer to produce anti-PD4-idiotypic antibody (alpha PD4-Ab2). The alpha PD4-Ab2 could not only competitively inhibit binding of McAb PD4 to gastric cancer cell MGC803, but also induce delayed-type hypersensitivity (DTH) to MGC803 in mice. Spleen cells of mice immunized with alpha PD4-Ab2 were fused with myeloma cell SP2/0 to form hybridoma secreting Ab3 which could be bound to target cell MGC803. McAb C7-Ab3, one of the Ab3, could selectively react with a 40 kD tumor-associated antigen located on MGC803 cell membrane, as well as McAb PD4. The results indicate that alpha PD4-Ab2 possesses determinants (internal image antigen) similar to those on MGC803, and could mimic human gastric cancer-associated antigen.

[Expression of the surface antigen in human gastric cancer cells and the relation to cell cycles--correlated analysis with flow cytometry]

Expression of tumor-associated antigen in different gastric cancer cell lines and different phases of cell cycle was studied cytochemically. The antigen was recognized by the monoclonal antibody (McAb) PC1 against gastric cancer cells. By using the McAb PC1 as first antibody, the indirect immunofluorescence stain and the peroxidase-anti-peroxidase (PAP) stain were done on the gastric cancer cell lines (MGC 803, SGC 7901 and BGC 823). It was shown that PC1 antigen was mainly expressed on the membrane of these cells and only a certain percentage of the cells gave the positive reaction with different intensities. It was obvious that the expression of PC1 antigen was heterogeneous in nature. The heterogeneity of the PC1 antigen expression in gastric cancer cells might be due to either various subpopulations in the cell lines or different phases of cell cycle. In order to go further into the question, we studied quantitatively the expression of PC1 antigen in gastric cancer cell lines (MGC 803, STC 7901 and BGC 823) and the relationship between the antigen expression and cell cycle by double fluorescence stain and two-dimensional flow cytometry. It was found that expression levels of PC1 antigen in these cell lines were in the following order: MGC 803 greater than SGC 7901 greater than BGC 823. The PC1 antigen predominantly expressed on G1 phase for MGC 803 and G1, G2-M phase for SGC 7901 respectively. And uniform low level of PC1 antigen expression was found for BGC 823 throughout the cell cycle. Therefore, the PC1 antigen expression is dependent on cell cycle in MGC 803 and SGC 7901 cell lines.

[Gastric cancer-associated antigen P42]

The corresponding antigen to monoclonal antibody PCI against gastric cancer cells was demonstrated as a protein sensitive to heating and easily degraded by proteinase. By western blotting, it was shown that the molecular weight of the antigen was 42 KD and the antigen was named P42. P42 could be shed into serum-free culture medium of the target cells and its activity be assayed in sera of the gastric cancer patients. Using inhibition test, the levels of P42-like substance in sera were measured. The results indicated that this level in the gastric cancer patients (26.53 +/- 23.11) was markedly higher than that in patients with benign gastric diseases (4.66 +/- 2.67) and controls (2.57 +/- 2.67). It is suggested that P42, a novel gastric cancer-associated antigen, be useful in the mass screening and supplementary in diagnosing gastric cancer.

[Preparation and identification of monoclonal antibody against the gastric cancer cell line MGC 803]

Spleen cells of Balb/c mice, immunized with gastric cancer cell MGC 803, were fused with murine myeloma cell NS-1. After selective culture, screening and subcloning, a hybridoma PC1 which produced monoclonal antibody (McAb) against MGC 803 cells was obtained. McAb PC1 bound strongly with 3/4 gastric cancer and 1/2 hepatoma cell lines, weakly with another gastric cancer and 2/2 lung cancer cell lines, but did not bind with the autologous and allogenic lymphocytes, ABO red blood cells, human fetal lung fibroblasts and normal bone marrow cells. The binding capacity of McAb PC1 to MGC 803 decreased significantly due to the absorption by MGC 803 cells, but was not affected by lymphocytes and CEA. The corresponding antigen of McAb PC1 was expressed on the surface of MGC 803 cells. It may be a gastric cancer-associated antigen.